1. Field of the Invention
The present invention relates to oil well pumps and more particularly to an improved hydraulic oil well pump that is electronically controlled using limit or proximity switches to control a valving arrangement that eliminates shock or excess load from the pumping string or sucker rod during pumping, and especially when changing direction of the sucker rod at the bottom of a stroke.
2. General Background of the Invention
Several patents have issued that relate generally to the pumping of oil from an oil well. Examples of those patents are contained in the following table, wherein the order of listing has no significance other than chronological.
TABLEPATENTISSUE DATENO.TITLEMM-DD-YY4,503,752Hydraulic Pumping Unit03-12-19854,761,120Well Pumping Unit and Control System08-02-19885,143,153Rotary Oil Well Pump and Sucker Rod Lift09-01-19925,390,743Installation and Method for the Offshore02-21-1995Exploitation of Small Fields6,394,461Pressure Compensated Stuffing Box for05-28-2002Reciprocating Pumping Units2003/Combination Well Kick Off and Gas Lift05-08-20030085036Booster Unit6,595,280Submersible Well Pumping System with an07-22-2003Improved Hydraulically Actuated SwitchingMechanism2005/Well Tubing/Casing Vibrator Apparatus07-21-20050155758